Protective cap for spray guns



April 14, 1942. r

A. EPPLER, JR

PROTECTIVE CAP FOR SPRAY GUNS Filed Jan. 10, 1940 Patented Apr. 14, 1942 UNITED, srrs PROTECTIVE CAP FOR SPRAY GUNS Andrew Eppler, Jr., Lynn, Mass, assignor to United Shoe Machinery Corporation, Borough of Flemington, N. J., a corporation of New Jersey Application January lli, 1e40, Serial No. 313,150 (01. 299-140) 3 Claims.

The present invention relates'to a closure and as herein illustrated is a protective cap particularly adapted to cover the nozzle or tip of a spray gun during the intervals of non-use.

The use of a pressure gun for spraying adhesive material, particularly latex, is accompanied by frequentdelay in the regular production of work as a result of the drying or coagulation of drops of the material at the nozzle of the gun. The accumulation is aggravated by intermittent use and makesit necessary for the operator to stop and clean the material from the tip before further operation. While the drops may be wiped from the discharge tip with waste or a piece of sponge, it requires an additional operation on the part of the operator after each use of the gun with a consequent loss of time. Furthermore, the repeated use of the wiping material soils the operators hands and ultimately the work.

It is an object of the present invention, therefore, to automatically cover the nozzle of the spray gun during intervals of non-use, thereby sealing the nozzle from exposure to the air so that any drops of material thereon will not dry or coagulate.

In accordance with this object, and as a feature of the invention, a protective cap is provided which is adapted to be held over the nozzle during the intervals of non-use of the gun, means being also provided by which the cap is moved from the position in which it covers the nozzle to a remote position during the operation of the gun. In order to effect this, the mechanism for operating the gun is interconnected with the means for moving the cap, whereby the cap is automatically removed from the discharge nozzle of the gun prior to its discharge and returned to cover the same immediately upon the cessation of the discharge.

For the specific construction and operation of the device, reference may be had to the accompanying drawing, in which Fig. l is an angular view of the device as associated with a spray gun mounted in a spray booth; and

Fig. 2 is an enlarged section of the protective cap shown in contact with the discharge nozzle of the gun.

The invention, as illustrated herein, is shown as applied to a spray gun I0, having a discharge valve l0 and a discharge nozzle II, the gun being mounted at the end of an arm l2 which in turn is supported on a rod I4 extending between the walls of a spray booth hood l8. Since the specific construction of this mounting forms no part of the present invention, it will not be described further.

The protective capis mounted so that it will normally cover the nozzle ll of the gun, the mechanism for operating the cap and gun being so interconnected that it is impossible to operate the gun without first having removed the cap or to replace the cap without first shutting off the gun.

To this end, the cap 28 is secured to one end of an arm 22 which is suspended from the end of a transverse spindle 24 journaled near its respective ends in a web 26 formed integral with the gun and an ear 28 formed on the side of the arm E2. The spindle may be turned in the bearings to move the arm 22 and, consequently, the cap 20, in an arc to and from the discharge nozzle H the rotation of the spindle being effected by a member 30 attached to the end of the spindle oppositethe arm 22. The member 3ll is the control handle of the gun and its operation actuates the gun discharge and the movements of the cap 28. In the illustrated embodiment of the invention this handle is connected by way of a'rod 32 to a sleeve 33 rotatably mounted on the rod I4, the sleeve in turn being connected to a foot treadle (not shown) by a succession of links and levers generally indicated L, whereby the member 3!] maybe turned.

The cap 20 is provided to prevent the access of air to the nozzle of the gun and since even under the best conditions there is bound to be some irregularity at thenozzle clue to incrustation, it is desirable to have a member which is somewhat resilient and which will yield and con form to the irregularities at the nozzle to give a good seal. It is also desirable that the sealing member have a certain amount of absorptive qualities in order to take up any drops of the material which may be present. Therefore, the cap is recessed at 35 and into this recess there is removably inserted a rubber cushion 36 to the outer face of which is'fixed a relatively stiff fiber plug 38 having a frusto-conical recess 40 in its free face for contact with the nozzle H of the gun. The fiber sealing surface has the additional advantage that it will not damage the nozzle of the gun by repeated contact therewith. After the fiber plug 38 has become worn or clogged up from repeated use, the plug and cushion 36 upon which it is mounted may be removed as a unit and replaced.

In order to connect the cap'and the valve stem of the gun to provide for the proper sequence of operations, a second spindle 42, parallel to the spindle 24, is journaled adjacent one end in the web 26 and adjacent the other end in an ear 44 The opposite end of the spindle 42 has fixed thereto a cam finger 54 the end of which lies in the pathof a cam surface 3| on the member 30, so that the'finger 54 will be lifted by. the me'mv ber 30 to turn the spindle 42. i

To spray material onto awork piece, the member 30 is turned in a downward direction by means of the treadle operated links L, sleeve 33 and arm 32. The initial movement ofthe member 30 'is communicated directly through vthe spindle 24 to the arm 22, whereby the cap'20 is' swung upwardly away from the nozzle ll; ,As movement of the member 3t! continues, the cam portion 3| thereof engages the cam finger 54 and the arm 46 is caused to operate the gunvalve stem I0, Sufficient lagv is provided between initial movement of the member 30 and engagement of the cam finger 54 to permit the cap to be moved entirely out of the range of the spray before the valve stem is operated to permit discharge of the spray. When the spraying operation has been completed, the operator releases the treadle, whereupon a spring (not shown) returns the members L to their normal inoperativepositions, and the member 30, is caused to turn in a reverse direction. During the initial reverse movement of the member 30, the cam surface 3| is disengaged from the cam finger 54 and the spring return within the'gun restores the valve stem ID to its neutral position. A spring 56 connected at its ends to the arm 22 and the arm 46 serves to returnthearm 4B and the cam finger 54 tothe inoperative position shown in Fig. 1. The final movement of thearm 30 brings the cap 20 into contact with thenozzlel I, the spring 55 urging the arm 22] toward a closed position and insuring a complete closure in case there is any slack in the operating members.

' Having described my invention, what I claim as new and desire to secure by Letters Patent of the United States is: l

' 1. A spray gun having a discharge valve and a the cap from the nozzle and thereafter to actuate said cam finger to open the discharge valve, and movement of the lever in the opposite direction operating first to release the cam finger to permit the discharge valve to close and thereafter to return the cap to cover the nozzle.

2. A spray gun having a dischargevalve and a nozzle, a cap for covering the nozzle mounted for movement toward and away therefrom, parallel spindles, means fixed to one of said spindles for operating the valve, a cam fingerfixed to the opposite end of said spindle, means fixed to one end of the other of said spindles for operating the cap, and common means fixed to the opposite end of the second-named spindle for turning the same, said common means having a cam formed integral therewith arranged to actuate said cam finger to turn the first-named spindle.

3. A spray gun having a discharge valve and a nozzle, a cap for covering the nozzle mounted for movement toward and away therefrom, parmember fixed to another portion of the second- 

